1. Technical Field
The disclosure relates to a vehicle in which a motor for traveling (traveling motor) and a power control unit for driving the motor are mounted in a front space of the vehicle.
2. Description of Related Art
Many vehicles that travel by using electric motors are in such a type that the electric motor and a power control unit for driving the motor are mounted in a front space (an engine compartment) of the vehicle. Note that the vehicle in this specification includes, in addition to an electric vehicle, a hybrid vehicle and a fuel cell vehicle. In addition, hereinafter, the “electric motor” will simply be described as the “motor” for simplification of the description. Furthermore, in this specification, according to a custom in a technical field of an automobile, a space for housing a traveling motor is described as the “engine compartment” regardless of whether an engine is actually mounted or not. In particular, in this specification, a motor housing space that is provided in a front section of the vehicle is described as the engine compartment.
The power control unit is typically an inverter that converts DC power of a power supply to AC power. The power control unit possibly includes a booster converter. The power control unit is possibly fixed above a housing that houses the motor. By arranging the power control unit near the motor, a power cable that connects the power control unit and the motor can be shortened, and thus loss in power transmission can be suppressed. One example of a vehicle that has an in-vehicle structure of the power control unit described above is disclosed in Japanese Patent Application Publication No. 2013-193634 (JP 2013-193634 A). In a technique disclosed in JP 2013-193634 A, a front portion and a rear portion of the power control unit are respectively supported by a front bracket and a rear bracket, and the power control unit is fixed with a gap being formed above the housing. A reason for securing the gap between the power control unit and the housing by the front bracket and the rear bracket is to suppress vibrations of the motor transmitted to the power control unit via the housing. Note that, in the following description, the front bracket and the rear bracket may simply be described as the “bracket” for convenience of the description when the front bracket and the rear bracket are not distinguished from each other. When both of the front bracket and the rear bracket are referred, they may be described as “both of the brackets”.
Components that handle power of tens of kilowatts exist in the power control unit. The power control unit is desired to be high in collision safety so that a high-voltage circuit therein is not exposed during a collision of the vehicle. In the case where the power control unit is mounted in the engine compartment, the collision safety thereof against a frontal collision (including an oblique collision) is particularly highly desired. The housing of the motor is relatively large and rigid. Thus, arrangement of the power control unit above the housing of the motor is also suited for protection of the power control unit from an obstacle that approaches from the front during the collision. However, even in such a case, there is a possibility that the obstacle passes above the housing during the frontal collision and the obstacle collides with the power control unit. The following disadvantage is present in such a structure that the power control unit is supported via both of the brackets with the gap being formed above the housing in the case where rigidity of each of the brackets is excessively high. More specifically, when the power control unit receives a collision load from the front during the frontal collision, there is a possibility that the load is concentrated on a coupling portion between the bracket and the housing and the coupling portion is damaged. For this reason, the bracket preferably has the strength in such a degree that it is bent when receiving the collision load of a specified magnitude or higher. By the way, in the case where both of the brackets are deformed and collapsed to the rear when the power control unit receives the collision load from the front, the power control unit moves to the rear. In the case where displacement of the power control unit is significant, an excessive tensile force is possibly applied to the power cable, to which a high voltage is applied.
In JP 2013-193634 A, a technique of reducing the tensile force that is applied to the power cable at the time when the power control unit moves to the rear during the collision is also disclosed.
One example of the bracket disclosed in JP 2013-193634 A has the following shape. Ribs that extend in a vertical direction are provided on both sides of the bracket when the bracket is seen from the front of the vehicle. A notch is provided near the center of each of the ribs in an extending direction. When the power control unit receives the collision load from the front, each of the brackets is collapsed to the rear in such a manner that an upper portion thereof above the notch draws an arc with the notch as a center. As a result, even when the brackets are collapsed, a connection distance of the power cable between the power control unit and the housing is retained to a distance that is at most equal to a distance before the collision. Thus, when the power control unit moves during the collision, application of the excessive tensile force to the power cable is prevented.